Hi bharath, I assume your budget of 15k is only for the sub, amp & front speaker.
In this budget, you can go for -
4 channel amp - JBL GT5-S644 - Rs. 5500-6000/-
Subwoofer - Infinity Ref 1260W - Rs. 6000/- or
JBL CS 1215 - Rs. 3500/-
Sealed enclosure for subwoofer - Rs. 500-1000/-
Front component speakers (discard your pioneer tweeter) - JBL GT5-S265C - Rs.4000/-
Wiring - Buy branded kit from Monster cables, earthquake or scosche if you can. This is very important.
Also, I am assuming your head unit is powerful enough to support all this.
Please discard your front pioneer tweeters & buy a component speaker as it comes with it's own tweeter, midbass & crossovers.
also, ensure that you have a good installer who can make you a good sealed enclosure for the sub, else buy a sub which comes with a factory supplied enclosure.
A sealed enclosure for the sub is good for sound quality, its gives a nice tight thump but wont be too loud. If you want your car to be loud, go for a ported enclosure. If you want your car to be even louder, go for a basstube (JBL CS1215T), which i wont recommend as it kills sound quality.
If you need to look at different brands, kindly have a look at this thread